International Patent Application No. US/95/03004 discloses a method for lining a toilet bowl with a thin film in the form of a continuous rectangular sheet supplied from a roll. A conveyance apparatus held and transported two opposed edges of the sheet around the perimeter of the bowl thus draping the sheet into the bowl to form a liner. The edges of the sheet were shown to be held by being impaled on pins which projected from two moving belts each of which traversed one half of the perimeter of the toilet bowl. The edges of the sheet were restrained from slipping off the pins by fixed guide surfaces which followed the path of the belts around the bowl and which would press lightly against the surface of the sheet near the pins to prevent the sheet from being dislodged from the pins.
That method of holding the edge of the liner sheet by piercing it with pins has several inherent complications which can require additional apparatus to correct and which can make the toilet more difficult to service. There is first the fact that some liner sheet material such as high density polyethylene can be tough, thin and slippery and will not puncture easily unless held under tension. Then, once the sheet is punctured by the point of the pin and is pushed further down the wider shank of the pin it will grip the pin to the extent that it will not easily come off, which it must do after being conveyed out of the bowl. Removal of the sheet from the pin is further restricted when the belt is on an outside bend which spreads the tips of the pins further apart requiring the sheet to stretch between adjacent pins. The solution to these problems requires additional apparatus to create the tension to facilitate the initial piercing by the pins and to create the mechanical forces required for removal of the sheet from the pins.
Furthermore, to service a film lined toilet it is desirable to be able to install a new roll of liner material with minimum difficulty, ideally with a feed mechanism requiring little or no manual intervention. The need for the liner sheet to be held under tension before the pins can pierce it and carry it forward makes it difficult to provide a feed mechanism that will work on the leading edge of the sheet which has no tension.